Nonsteroidal anti-inflammatory drugs in orthodontic tooth movement: metalloproteinase activity and collagen synthesis by endothelial cells

Metalloproteases in Pain Generation and Persistence: A Possible Target?

Matrix metalloproteinases (MMPs) are a large family of zinc-dependent proteolytic enzymes associated with extracellular matrix protein turnover and tissue degradation. They participate to many different physiological reactions but are also hyperactivated in several diseases. Various literature studies have documented that MMPs play a role in the modulation of neuropathic and nociceptive pain. The heterogeneity of clinical and pre-clinical data is an important issue in this experimental context. Despite the presence of a good number of studies on MMP inhibitors, these drugs showed scarce efficacy and relevant side effects. In the present manuscript, we reviewed studies in the literature that define a possible role of MMPs in pain and the effects of their modulation.

The efficacy of analgesics in controlling orthodontic pain: a systematic review and meta-analysis

Background

Patients who had gone through orthodontic treatment experienced pain and discomfort which could be the highest-ranking reason for treatment disturbance or early termination. Thus, this review aimed to assess the efficacy of analgesics on the relief of pain in orthodontic treatment.

Methods

A computerized literature search was conducted in the databases of EMBASE (via OVID, 1974 to 2019 Week 50), MEDLINE (via OVID, 1946 to Dec 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (December 2019). The Cochrane Collaboration’s Review Manager 5.3 software was applied in the present study. And methodological quality was evaluated by the Cochrane Risk of Bias Tool.

Results

We identified twelve publications including 587 patients in 19 randomized controlled trials. The results showed that the mean difference of naproxen in visual analogue scale (VAS) were − 1.45 (95% CI -2.72, − 0.19; P = .02), − 2.11 (95% CI -3.96, − 0.26; P = .03) and − 1.90 (95% CI -3.33, − 0.47; P = .009) in 2 h, 6 h and 24 h respectively. As for ibuprofen, the standard mean differences were − 1.10 (95% CI -1.49, − 0.71), − 1.63(95% CI -2.32, − 0.95) and − 1.34 (95% CI -2.12, − 0.55) at 2 h, 6 h, and 24 h, with the overall P values all < 0.001. The mean difference of acetaminophen is − 0.68, − 1.34, − 1.91 at three time points and the overall P values all < 0.01.

Conclusions

This meta-analysis suggests that the use of analgesics is effective for patients in controlling orthodontic pain. Ibuprofen and naproxen are both of stable analgesic effects which could peak at 6 h, while the analgesic effect of acetaminophen increases steadily from 2 h through 24 h. Compared with ibuprofen and acetaminophen, naproxen shows a stronger analgesic effect either at 2 h or 6 h, and its effect lasts to 24 h.

Influence of photobiomodulation on pain perception during initial orthodontic tooth movement

Abstract Introduction Laser in low intensity (LLI) has been used to reduce the discomfort and pain that is triggered by the forces applied during orthodontic treatment. Objective To evaluate the effect of LLI application in the pain perception of periodontal ligament initial compression, during orthodontic tooth movement; and to compare the effect of this therapy between men and women. Material and method The sample consisted of 30 volunteers, who needed orthodontic band placement on mandibular first molars. After insertion of the elastic separators, LLI was applied to the mesial and distal apical region (wavelength 808nm, energy 2J, time 20s and fluency of 8.32J/cm2) and at three points on the root region (wavelength 808nm, energy 1J, time 10s and fluency of 4.16J/cm2) of the first molar (irradiated side) and compared to the contralateral first molar (non-irradiated side), in three time intervals: 0hs, 24hs and 48hs. Pain perception was evaluated by the Visual Analog Scale (VAS), at 0hs, 24hs and 48hs after insertion, with significance of 5%. Result The pain level was observed to be significantly lower (p<0.05) on the irradiated side, irrespective of gender and time. Women presented a significantly higher pain level (p<0.05) than men, irrespective of time and side. There were no significant differences between the time intervals (p>0.05). Conclusion It was concluded that LLI reduced the perception of initial pain in patients in whom compression of the periodontal ligament was promoted by elastic separation, and that women had a greater perception of pain sensitivity in the time intervals studied.

Does medication administration affect the rate of orthodontic tooth movement and root resorption development in humans? A systematic review

Background

Recently, the potential impact of different medications on the rate of orthodontic tooth movement and the associated root resorption has been systematically reviewed in animal studies and various effects have been shown. However, animal data cannot be extrapolated to human clinical situations directly.

Objectives

To systematically investigate the most up to date available evidence from controlled human studies regarding the effect of medication administration on the rate of orthodontic tooth movement and associated root resorption development.

Search methods

We searched eight databases (covering also grey literature) without restrictions and we performed hand searching up until October 2018.

Selection criteria

Controlled studies in humans assessing the effect of various medications on the rate of orthodontic tooth movement and root resorption development.

Data collection and analysis

Study selection was followed by data extraction and risk of bias assessment using the ROBINS-I tool for non-randomized and the Cochrane Risk of Bias Tool for randomized studies.

Results

Eight studies, at various risk of bias, were finally identified. With regard to the rate of orthodontic tooth movement, local injections of prostaglandin E1 were found to exert an increasing effect, whereas systemic intake of nabumetone decreased it. Following tenoxicam administration, drinking water with fluoride or local injections of calcitriol (vitamin D metabolite), no significant effects were demonstrated. Concerning root resorption development, nabumetone administration was shown to reduce it, whereas fluoride, overall, was not observed to exert any effect. Only in individuals subjected to heavy orthodontic forces, did fluoride show a protective effect for the period of force application, but not in the longer term during retention.

Conclusions

The aforementioned substances may show varying effects on the rate of orthodontic tooth movement and root resorption development in human subjects. Despite the observed limitations, the orthodontist should be able to identify patients taking pharmaceuticals and consider any implications related to orthodontic treatment.

Registration

PROSPERO (CRD42017078208).

Medication and orthodontic tooth movement

As any pharmaceutical substance may influence the events associated with orthodontic tooth movement, it is of importance for the clinician to be able to recognize any prospective patient's history and patterns of medicinal consumption. This review presents the effects of various commonly prescribed medications on the rate of orthodontic tooth movement. The article concludes that it remains, to a degree, unclear which types of medication may have a clinically significant effect in everyday clinical scenarios. However, since both prescription and over-the-counter medication use have recently increased significantly among all age groups, good practice suggests that it is important to identify patients consuming medications and consider the possible implications in orthodontic therapy.

Does long-term use of pain relievers have an impact on the rate of orthodontic tooth movement? A systematic review of animal studies

Background

Pain relief drugs are used and misused widely and may theoretically affect the events leading to orthodontic tooth movement.

Objective

To systematically investigate and appraise the quality of the available evidence regarding the effect of pain relief medications on the rate of orthodontic tooth movement.

Search methods

Search without restrictions in eight databases (including grey literature) and hand searching until October 2018.

Selection criteria

Animal controlled studies investigating the effect of pain relievers on the rate of orthodontic tooth movement.

Data collection and analysis

Following study retrieval and selection, relevant data were extracted and the risk of bias was assessed using the SYRCLE’s risk of bias tool.

Results

Fourteen studies were finally identified, most of which at unclear risk of bias. Ibuprofen and loxoprofen did not show any significant effects on the rate of orthodontic tooth movement, whereas indomethacin, ketorolac, morphine, and high doses of etoricoxib were found to decrease it. Inconsistent or conflicting effects were noted after the administration of acetaminophen, acetylsalicylic acid, celecoxib, meloxicam, and tramadol. The quality of the available evidence was considered at best as low.

Conclusions

Long-term consumption of pain relievers may affect the rate of orthodontic tooth movement. The orthodontist should be capable of identifying patients taking pain relievers independently of orthodontic treatment and consider the possible implications.

Trial registration

PROSPERO (CRD42017078208).

Effects of single-dose, low-level laser therapy on pain associated with the initial stage of fixed orthodontic treatment: A randomized clinical trial

Objective

The aim of this study was to assess the analgesic effect of a single application of low-level laser therapy (LLLT) on spontaneous pain and pain on chewing after placement of initial archwires.

Methods

Forty-two patients (26 women, 16 men) were randomly recruited for this split-mouth randomized clinical trial. Each patient received super-elastic nickel-titanium (NiTi) initial archwires (0.012, 0.014, 0.016, and 0.018-inch [in]) in the maxilla for leveling and alignment for an interval of 4 weeks between archwires. One side of the mouth was randomly designated as experimental, while the other side served as placebo. After insertion of each archwire, the experimental side was irradiated with a diode laser for 3 seconds each on 5 points facially and palatally per tooth, from the central incisor to first molar. On the placebo side, the laser device was held the same way but without laser application. A numerical rating scale was used to assess the intensity of spontaneous and masticatory pain for the following 7 days. The Mann-Whitney U test was used to compare pain scores between sides.

Results

Patients in the LLLT group exhibited significantly lower mean scores for spontaneous pain after insertion of the initial two archwires (0.012-in and 0.014-in NiTi; p < 0.05), while there was no significant difference for 0.016-in and 0.018-in wires between the LLLT and placebo groups. LLLT significantly reduced chewing pain scores (p < 0.05) for all archwires.

Conclusions

A single dose of LLLT considerably lessened postoperative pain accompanying the placement of super-elastic NiTi wires for initial alignment and leveling.

Current advances in orthodontic pain

Orthodontic pain is an inflammatory pain that is initiated by orthodontic force-induced vascular occlusion followed by a cascade of inflammatory responses, including vascular changes, the recruitment of inflammatory and immune cells, and the release of neurogenic and pro-inflammatory mediators. Ultimately, endogenous analgesic mechanisms check the inflammatory response and the sensation of pain subsides. The orthodontic pain signal, once received by periodontal sensory endings, reaches the sensory cortex for pain perception through three-order neurons: the trigeminal neuron at the trigeminal ganglia, the trigeminal nucleus caudalis at the medulla oblongata and the ventroposterior nucleus at the thalamus. Many brain areas participate in the emotion, cognition and memory of orthodontic pain, including the insular cortex, amygdala, hippocampus, locus coeruleus and hypothalamus. A built-in analgesic neural pathway—periaqueductal grey and dorsal raphe—has an important role in alleviating orthodontic pain. Currently, several treatment modalities have been applied for the relief of orthodontic pain, including pharmacological, mechanical and behavioural approaches and low-level laser therapy. The effectiveness of nonsteroidal anti-inflammatory drugs for pain relief has been validated, but its effects on tooth movement are controversial. However, more studies are needed to verify the effectiveness of other modalities. Furthermore, gene therapy is a novel, viable and promising modality for alleviating orthodontic pain in the future.

Does low level laser therapy relieve the pain caused by the placement of the orthodontic separators?--A meta-analysis

OBJECTIVE

Pain caused by orthodontic treatment can affect patient's compliance and even force them to terminate treatments. The aim of this meta-analysis is to evaluate of the analgesic effect of low level laser therapy (LLLT) after placement of the orthodontic separators.

METHODS

Five databases: PubMed, Embase, Cochrane library, China Biology Medicine disc (SinoMed CBM), China National Knowledge Infrastructure (CNKI) were searched for all the appropriate studies in June, 2014. Two reviewers screened the research results under our inclusion criteria and evaluated the risk of bias independently. Then the data of the included studies was extracted for quantitative analysis by the Review Manager 5.1 software.

RESULTS

Six studies were included in our meta-analysis finally. Comparing to the placebo group, the LLLT has good analgesic effect at 6 h, 1d, 2d, 3d after placement of separators which is of statistical significance. While at 2 h, 4d, 5d after the placement, the results tend to support LLLT, but not statistically significant.

CONCLUSION

Based on current included studies, LLLT can reduce the pain caused by the placement of separators effectively. However, because of the high heterogeneity, well designed RCTs are required in the future.

Estimation of alkaline phosphatase in the gingival crevicular fluid during orthodontic tooth movement in premolar extraction cases to predict therapeutic progression

OBJECTIVES

The objective was to estimate the level of alkaline phosphatase (ALP) in gingival crevicular fluid (GCF) during en-masse retraction stage of orthodontic tooth movement.

MATERIALS AND METHODS

10 patients in the age group of 15-20 years participated in this study. GCF was sampled from the distal surface of the canine and mesial surface of the second premolar on day 0, 1, 7, 14, 21, and 28 postorthodontic treatment.

RESULTS

A marked fall in the level of ALP was evident following force application. A progressive decreasing trend in ALP activity on both distal aspect of canine and mesial aspect of the second premolar was observed. The fall in ALP was more on distal aspect canine when compared to the mesial aspect of the second premolar.

CONCLUSIONS

Measure of ALP activity in GCF could be an indicator of the biochemical and cellular alterations in bone turnover and hence rate the amount of tooth movement following orthodontic force application.

Effect of frequent laser irradiation on orthodontic pain. A single-blind randomized clinical trial

OBJECTIVE

To analyze the effect of low-level laser therapy (LLLT) on perception of pain after separator placement and compare it with perceptions of control and placebo groups using a frequent irradiation protocol.

MATERIALS AND METHODS

Eighty-eight patients were randomly allocated to a laser group, a light-emitting diode (LED) placebo group, or a control group. Elastomeric separators were placed on the first molars. In the laser and LED groups, first molars were irradiated for 30 seconds every 12 hours for 1 week using a portable device. Pain was marked on a visual analog scale at predetermined intervals. Repeated measure analysis of variance was performed for statistical analysis.

RESULTS

The pain scores of the laser group were significantly lower than those of the control group up to 1 day. The pain scores in the LED group were not significantly different from those of the laser group during the first 6 hours. After that point, the pain scores of the LED group were not significantly different from those of the control.

CONCLUSIONS

Frequent LLLT decreased the perception of pain to a nonsignificant level throughout the week after separator placement, compared with pain perception in the placebo and control groups. Therefore, LLLT might be an effective method of reducing orthodontic pain.

Toll-like receptor activation and mechanical force stimulation promote the secretion of matrix metalloproteinases 1, 3 and 10 of human periodontal fibroblasts via p38, JNK and NF-kB

Matrix metalloproteinases (MMPs) are known to play a key role during orthodontic treatment leading to periodontal remodelling and tooth movement. MMPs may be induced by mechanical forces. However, the role played by toll-like receptors (TLRs) in modulating the effects of the mechanical force on periodontal fibroblasts is not known. To investigate the interaction between mechanical force and TLR stimulation, primary cultures of human periodontal fibroblasts were submitted to centrifugation in the presence of LPS and Pam3Cys, which are known TLR-4 and TLR-2 ligands, respectively. The expression of MMP-1, -2, -3, -8, -9, -10 and -13; TIMP (Tissue Inhibitor of Metalloproteinases) -1, -2 and -4; TNF-α (Tumour Necrosis Factor alpha); IL-1β (Interleukin 1 beta); ERK 1/2 (Extracellular Signal-Regulated Kinase 1/2); p38; JNK (c-jun N-terminal Kinase); IRAK1 (Interleukin-1 Receptor-Associated Kinase); and NF-κB (Nuclear Factor kappa B) were measured by antibody array, ELISA and immunoblotting methods. The activation of TLRs associated with centrifugation induced an increase in the secretion of MMPs 1, 3 and 10, with no increase in TNF-α or IL-1β. An increase in the phosphorylation of the MAP kinases p38 and JNK and the transcription factor NF-κB, without an increase in TIMPs was also observed. These findings suggest that the secretion of MMPs by cultured periodontal fibroblasts that is induced by combined TLR activation and mechanical force stimulation is regulated via the p38, JNK and NF-κB pathways. The increased secretion of MMPs by TLR activation may be an important factor that should be considered during orthodontic treatment.

Crevicular Alkaline Phosphatase Activity and Rate of Tooth Movement of Female Orthodontic Subjects under Different Continuous Force Applications

Purpose. This study is aimed to compare the effects of two different orthodontic forces on crevicular alkaline phosphatase activity, rate of tooth movement, and root resorption. Materials and Methods. Twelve female subjects of class II division 1 malocclusion participated. Maxillary canines with bonded fixed appliances acted as the tested teeth, while their antagonists with no appliances acted as the controls. Canine retraction was performed using nickel titanium coil spring that delivered forces of 100 gm or 150 gm to either side. Crevicular fluid was analyzed for ALP activity, and study models were casted to measure tooth movements. Root resorption was assessed using periapical radiographs before and after the force application. Results. ALP activity at the mesial sites peaked at week 1 for 150 gm group with significant differences when compared with the 100 gm group. Cumulative canine movements were significantly greater in the 150 gm force (2.10 ± 0.50 mm) than in the 100 gm force (1.57 ± 0.44 mm). No root resorption was in the maxillary canines after retraction. Conclusions. A force of 150 gm produced faster tooth movements and higher ALP activity compared with the 100 gm group and had no detrimental effects such as root resorption.

Effects of a Mikania laevigata extract on bone resorption and RANKL expression during experimental periodontitis in rats

Objectives

The Mikania laevigata extract (MLE) (popularly known in Brazil as "guaco") possesses anti-inflammatory properties. In the present study we tested the effects of MLE in a periodontitis experimental model in rats. We also investigated possible mechanisms underlying such effects.

Material and Methods

Periodontal disease was induced by a ligature placed around the mandibular first molars of each animal. Male Wistar rats were divided into 4 groups: non-ligated animals treated with vehicle; non-ligated animals treated with MLE (10 mg/kg, daily); ligature-induced animals treated with vehicle and ligature-induced animals treated with MLE (10 mg/kg, daily). Thirty days after the induction of periodontal disease, the animals were euthanized and mandibles and gingival tissues removed for further analysis.

Results

Morphometric analysis of alveolar bone loss demonstrated that MLE-treated animals presented a decreased alveolar bone loss and a lower expression of the activator of nuclear factor-κB ligand (RANKL) measured by immunohistochemistry. Moreover, gingival tissues from the MLE-treated group showed decreased neutrophil migration myeloperoxidase (MPO) assay.

Conclusions

These results indicate that MLE may be useful to control bone resorption during progression of experimental periodontitis in rats.

Pentraxin-3 levels in gingival crevicular fluid during orthodontic tooth movement in young and adult patients

OBJECTIVES

To measure the levels of pentraxin-3 (PTX-3) in gingival crevicular fluid (GCF) in orthodontic young and adult patients in the first 2 weeks after the orthodontic appliance to determine whether those changes occur during orthodontic treatment and if those values could be the expression of an inflammatory state.

MATERIALS AND METHODS

GCF samples were collected with paper strips from 16 orthodontic young patients and 13 orthodontic adult patients from an upper canine requiring distalization as a test tooth. A contralateral canine was used as a control tooth. The absorbed volume was eluted in 100 µL phosphate-buffered saline (pH  =  7.2). PTX-3 levels in GCF were determined using a commercial enzyme-linked immunosorbent assay kit, and the results were expressed in ng/mL.

RESULTS

The results showed an increase of GCF levels of PTX-3 from 1 hour before the orthodontic appliance to a maximum at 24 hours, followed by a decrease in both groups of adult and young patients.

CONCLUSIONS

The results suggest PTX-3 involvement in periodontal orthodontic remodeling and the aseptic inflammation induced by the orthodontic forces.

Effects of analgesics on orthodontic pain

INTRODUCTION

Our objective was too assess the effectiveness of 3 analgesics (ibuprofen, naproxen sodium, and acetaminophen) and a placebo administered before and after the placement of separators in reducing the severity of postseparator placement pain. We also examined the impact of treatment on chewing efficiency at 24 hours after separator placement.

METHODS

Twenty-four subjects participated in the study. Each subject received 3 of 4 treatments: ibuprofen, naproxen sodium, acetaminophen, or placebo in random order at monthly intervals. The dosing times were 1 hour before separator placement and 3 and 7 hours after separator placement. Before placement, the subjects completed a masticatory efficiency test and a visual analog scale (VAS) for expected pain and pain experienced. A VAS pain diary was kept for 24 hours. Subjects returned to the clinic after 1 week for separator removal.

RESULTS

VAS pain summary scores after separator placement were significantly affected by the administration of ibuprofen (P = 0.0298) and the time after separator placement (P <0.0001). Administering ibuprofen before and after separator placement significantly reduced pain compared with the placebo. The analgesic effects diminished by day 2, resulting in peak pain levels and decreased chewing efficiency. The expected pain after separator placement also played a role in experienced pain; subjects expecting more pain experienced more pain.

CONCLUSIONS

Ibuprofen was superior to the placebo in relieving postseparator pain as measured by the VAS pain summary scores, whereas acetaminophen and naproxen sodium did not significantly differ from the placebo.

Interventions for pain during fixed orthodontic appliance therapy. A systematic review

OBJECTIVE

To compare the different methods of pain control intervention during fixed orthodontic appliance therapy.

MATERIALS AND METHODS

A computerized literature search was performed in MEDLINE (1966-2009), The Cochrane Library (Issue 4, 2009), EMBASE (1984-2009), and CNKI (1994-2009) to collect randomized controlled trials (RCTs) for pain reduction during orthodontic treatment. Data were independently extracted by two reviewers and a quality assessment was carried out. The Cochrane Collaboration's RevMan5 software was used for data analysis. The Cochrane Oral Health Group's statistical guidelines were followed.

RESULTS

Twenty-six RCTs were identified and six trials including 388 subjects were included. Meta-analysis showed that ibuprofen had a pain control effect at 6 hours and at 24 hours after archwire placement compared with the placebo group. The standard mean difference was -0.47 and -0.48, respectively. There was no difference in pain control between ibuprofen, acetaminophen, and aspirin. Other analgesics such as tenoxicam and valdecoxib had relatively lower visual analog scale (VAS) scores in pain perception. Low-level laser therapy (LLLT) was also an effective approach for pain relief with VAS scores of 3.30 in the LLLT group and 7.25 in the control group.

CONCLUSIONS

Analgesics are still the main treatment modality to reduce orthodontic pain despite their side effects. Some long-acting nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclo-oxygenase enzyme (COX-2) inhibitors are recommended for their comparatively lesser side effects. Their preemptive use is promising. Other approaches such as LLLT have aroused researchers' attention.

Polarized light microscopic analysis of bone formation after inhibition of cyclooxygenase 1 and 2

Potassium diclofenac is a potent nonsteroidal anti-inflammatory drug (NSAID) and COX isoforms (COX-1 and COX-2) inhibitor. Quantitative analysis of birefringence with polarized light microscopy is a useful method to investigate the macromolecular orientation and organization of collagen fibers in connective tissues. The aim of this research was to analyze the collagen structure and maturation in bone formed after potassium diclofenac administration, during first molar orthodontic movement. Sixty Wistar rats were divided in two equal groups (N = 30): control (C) and potassium diclofenac (PD). The animals in Group C received 0.9% saline solution and the PD group received potassium diclofenac Cataflam (5 mg/kg). Animals were sacrificed 3, 7, or 14 days after a NiTi unilateral closed-coil spring was stretched between the upper right first molar and the incisors. The first molar area was fixed, decalcified, and histologically processed using picrosirius pigment. The collagen birefringence of bone turnover was analyzed by phase retardation. Two-way ANOVA and Tukey's test showed that optical retardation was influenced by time and treatment. There was increase in the collagen organization over time. On the third day, the C group showed better collagen organization than the PD group. Potassium diclofenac interfered in collagen maturation, reducing fibril organization in the initial phase of orthodontic movement.

Ibuprofen upregulates expressions of matrix metalloproteinase-1, -8, -9, and -13 without affecting expressions of types I and III collagen in tendon cells

Nonsteroidal antiinflammatory drugs are widely used to treat sports-related tendon injuries or tendinopathy. This study was designed to investigate the effect of ibuprofen on expressions of types I and III collagen, as well as collagen-degrading enzymes including matrix metalloproteinase (MMP)-1, -2, -8, -9, and -13. Rat Achilles tendon cells were treated with ibuprofen and then underwent MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Reverse transcription-polymerase chain reaction was used to evaluate mRNA expressions of types I and III collagen, MMP-1, -2, -8, -9, and -13. Protein expressions of types I and III collagen, MMP-1, -8, and -13 were determined by Western blot analysis. Gelatin zymography was used to evaluate the enzymatic activities of MMP-2 and MMP-9. The results revealed that ibuprofen upregulated expressions of MMP-1, -8, -9, and -13, both at mRNA and protein levels. There was no effect of ibuprofen on mRNA and protein expressions of types I and III collagen. Gelatin zymography revealed that the enzymatic activity of MMP-9 was upregulated after ibuprofen treatment. In conclusion, ibuprofen upregulates the expressions of collagenases including MMP-1, -8, -9, and -13 without affecting the expressions of types I and III collagen. These findings suggest a molecular mechanism potentially accounting for the inhibition of tendon healing by ibuprofen.

Matrix metalloproteinase 2 activity decreases in human periodontal ligament fibroblast cultures submitted to simulated orthodontic force

Orthodontic force compresses the periodontal ligament promoting the expression of pro-inflammatory mediators and matrix metalloproteinases responsible for tooth movement. The extent in time while periodontal cells are being treated and the increment in the amount of mechanical stress caused by the orthodontic force is thought to regulate the levels of metalloproteinases in the periodontal tissue. To study the possible regulation in the activity of metalloproteinases 2, 3, 7, 9, and 10 by simulated orthodontic force, human periodontal ligament fibroblast cultures were centrifuged (141 × g) for 30, 60, 90, and 120 min, simulating the orthodontic force. Cell viability, protein quantification, and activity of metalloproteinases by zymography were evaluated at 24, 48, and 72 h after centrifugation in both cell lysates and growth medium. The activity of the 72-kDa matrix metalloproteinase 2 was decreased at 24 h regardless of the duration of centrifugation and at 48 h in cells centrifuged for 30 min only. Decrease in the amount of total protein in lysates was seen at 48 and 72 h with no change in cell viability. The data seem to indicate that the amount of mechanical stress regulates the levels of secreted matrix metalloproteinase 2. In addition, the centrifugation as a model for simulated orthodontic force may be used as a simple and reliable method to study the role played by matrix metalloproteinases in periodontal ligament when submitted to mechanical force as occurring during tooth movement.

Comparison of the efficacy of ibuprofen and acetaminophen in controlling pain after orthodontic tooth movement

INTRODUCTION

Some patients undergoing orthodontic treatment report enough discomfort to affect their compliance or request treatment termination. The purpose of this preliminary study was to test the effectiveness of ibuprofen vs acetaminophen in controlling discomfort after initial orthodontic appliance and archwire placement.

METHODS

A total of 60 patients (ages, 12-18 years) undergoing fixed comprehensive orthodontic treatment were randomly assigned to 1 of 3 experimental groups: 600 mg of acetaminophen, 400 mg of ibuprofen, or a placebo. All subjects were instructed to take the medications orally at prescribed times after initial appliance and archwire placement. Each patient's level of discomfort was assessed with a 100-mm visual analog scale immediately after placement; at 3, 7, 19, 24, 31, and 48 hours; and at 3, 4, and 7 days.

RESULTS

The results indicated that the peak level of pain was at 19 hours after placement, and the differences in scores among the 3 groups were not statistically significant.

CONCLUSIONS

Acetaminophen, ibuprofen, and placebo are equally effective in reducing discomfort after initial orthodontic appliance placement.

Orthodontic treatment of patients using bisphosphonates: A report of 2 cases

The pharmacologic agent bisphosphonate has recently received much attention in the dental literature. Bisphosphonates in oral or intravenous forms are used to treat various diseases such as certain cancers, bone- and calcium-related disorders, osteoporosis, and osteopenia. Bisphosphonates inhibit bone turnover and result in increased bone-mineral density. The most serious dental side effect of bisphosphonate treatment (particularly when it is administered intravenously) is, paradoxically, osteonecrosis of the mandible or the maxilla represented by exposed nonhealing bone. Other related complications include decreased bone healing and inhibition of orthodontic tooth movement. This article reports the orthodontic treatment of 2 patients who were taking bisphosphonates.

The effect of drugs on orthodontic tooth movement

OBJECTIVE

Molecules produced in various diseased tissues, or drugs and nutrients consumed regularly by patients, can reach the mechanically stressed paradental tissues through the circulation, and interact with local target cells. The combined effect of mechanical forces and one or more of these agents may be inhibitory, additive or synergistic. The objective of this review is to outline the mechanisms of action and effects of some commonly used drugs on tissue remodeling and orthodontic tooth movement.

DESIGN

All the existing published literature on the effects of various drugs that are prescribed by orthodontists, which are consumed by patients for systemic diseases and those that are known to promote and retard the tooth movement process was obtained and subjected to thorough review process.

RESULTS

All the drugs reviewed have therapeutic effects, as well as side effects, that may influence the cells targeted by orthodontic forces. Therefore, it is imperative that the orthodontist pays close attention to the drug consumption history of each and every patient, before and during the course of orthodontic treatment. When the use of drugs is revealed, their effects and side effects on tissue systems should be explored, to determine their potential influence on the outcome of mechanotherapy.

CONCLUSION

Drug-consumption history must be an integral part of every orthodontic diagnosis and treatment plan.

Current concepts in the biology of orthodontic tooth movement

Adaptive biochemical response to applied orthodontic force is a highly sophisticated process. Many layers of networked reactions occur in and around periodontal ligament and alveolar bone cells that change mechanical force into molecular events (signal transduction) and orthodontic tooth movement (OTM). Osteoblasts and osteoclasts are sensitive environment-to-genome-to-environment communicators, capable of restoring system homeostasis disturbed by orthodontic mechanics. Five micro-environments are altered by orthodontic force: extracellular matrix, cell membrane, cytoskeleton, nuclear protein matrix, and genome. Gene activation (or suppression) is the point at which input becomes output, and further changes occur in all 5 environments. Hundreds of genes and thousands of proteins participate in OTM. Gene-directed protein synthesis, modification, and integration form the essence of all life processes, including OTM. Bone adaptation to orthodontic force depends on normal osteoblast and osteoclast genes that correctly express needed proteins at the right times and places. Cell membrane receptor-ligand docking is an important initiator of signal transduction and a discovery target for new bone-enhancing drugs. Despite progress in identification of regulatory molecules, the genetic mechanism of "orchestrated synthesis" between different cells, tissues, and systems remains largely unknown. Interpatient variation in mechanobiological response is most likely due to differences in periodontal ligament and bone cell populations, genomes, and protein expression patterns. Discovery of mutations in OTM-associated genes of orthodontic patients, including those regulating osteoclast bone-matrix acidification, chloride channel function, and osteoblast-derived mineral and protein matrices, will permit gene therapy to restore normal matrix and protein synthesis and function. Achieving selectivity in targeting abnormal genes, cells, and tissues is a major obstacle to safe and effective clinical application of gene engineering and stem-cell mediated tissue growth. Orthodontic treatment is likely to evolve into a combination of mechanics and molecular-genetic-cellular interventions: a change from shotgun to tightly focused communication with OTM cells.

A influência de medicamentos na movimentação ortodôntica: uma análise crítica da literatura

Neste trabalho analisou-se criteriosamente a literatura pertinente sobre a influência de medicamentos na movimentação dentária induzida, avaliando os métodos experimentais para correlacioná-los com a aplicabilidade e extrapolação para a clínica ortodôntica. Devido aos trabalhos experimentais serem feitos em animais, que têm um tempo de vida curto, as doses dos medicamentos são elevadas e os períodos de administração muito longos. Portanto, não se pode afirmar sobre qualquer alteração na movimentação dentária induzida causada por algum tipo de medicamento que o paciente faça uso durante o tratamento ortodôntico.

Healing responses of skin and muscle in critical illness

OBJECTIVE

Many aspects of the care and underlying pathologies in patients suffering critical illness can detrimentally influence the normal healing processes of skin and soft tissues. Although a great diversity of pathologies exists, some aspects of the diseases and their treatments are common in critically ill patients. We aimed to identify some features, both common and specific, that could influence wound healing and the mechanisms by which they may do so.

DESIGN

In this review, we first outline the biology of normal skin and muscle healing and then explore how critical illness may influence the normal healing cascade.

FINDINGS

The healing of skin and skeletal muscle in critical illness is influenced by both underlying disease processes and the intensive care environment. Local and systemic factors can contribute to impaired healing, with the potential to prolong functional disability and increase the likelihood of wound complications. The frequency and number of soft tissue injuries derived from accidental injury, surgical intervention, and the need for invasive monitoring and therapies in the intensive care unit setting are likely to compromise the innate immunity and potentially further jeopardize the patient's ability to heal. Alterations in coagulation, tissue perfusion, inflammation, immune functioning, metabolism, nutrition, and drug therapies will influence healing responses by modifying the biological responses to tissue disruption. Locally, wound contamination, sepsis, tissue hypoxia, edema, and excessive or prolonged local pressure all have the potential to compromise soft tissue healing. One or more of these factors may be present at any time.

CONCLUSION

The skin and soft tissues are vulnerable to both injury and compromised healing when a patient is critically ill and exposed to a critical care environment. The identification of risk factors may aid in forming and modifying treatment strategies when caring for the critically ill patient with soft tissue injuries.

The effect of retention on orthodontic relapse after the use of small continuous or discontinuous forces. An experimental study in beagle dogs

Relapse is a major concern in orthodontics for which avoidance retention is the general procedure. However, the effect of retention on relapse after active tooth movement with different force regimes has never been studied in a standardized experimental setting. Mandibular third premolars were extracted in 19 young adult beagle dogs. Three months later, the second premolars were bodily moved distally with forces of 10 cN or 25 cN. The forces were applied for 24 h d-1 or for 16 h d-1. After 4 months, relapse was allowed in half of the animals, while in the others relapse was preceded by retention for 90 d. Statistical analyses were performed on the relation between force regime, active tooth movement, retention, and relapse. Force magnitude had no effect on relapse, while continuous forces resulted in a longer-lasting and more pronounced relapse than did discontinuous forces. A significant positive correlation was found between the amount of active tooth movement and both the rate and the total amount of relapse, but not between the amount of active tooth movement and the duration of the relapse. Retention had no effect on the duration of the relapse, but it strongly decreased its total amount. Finally, the effect of retention on the amount of relapse was strongly correlated with the amount of active tooth movement.